Forty percent of surveyed employees at the troubled agency received improper reimbursements, the county auditor-controller found. Supervisors admit not reviewing the reports.

Forty percent of surveyed employees at Los Angeles County's troubled child welfare agency improperly received mileage reimbursements from taxpayers on days they did not work, according to a sample of reimbursement reports for 20 employees with high mileage claims examined by the county auditor-controller.

Thirteen supervisors responsible for signing off on the reports acknowledged that they routinely did not review them first, the study found. The majority of reviewed reports vastly overstated the distance between travel points, and nearly half the reviewed reimbursement requests lacked basic information.

The department has 3,000 employees who use their personal vehicles for county business, and taxpayers reimbursed them $7.7 million during the last fiscal year alone.

Auditor-Controller Wendy Watanabe said "significant weaknesses" in reimbursement procedures had fostered fraud and "may have been prevented with proper management oversight."

After the report was issued online, however, she cautioned that her audit was based on a "non-scientific sample" and said that the 20 reviewed employees had been selected because they had "historically higher than average amounts of mileage reimbursement requests."

The findings were based on a detailed review of records for the 20 employees and mark the latest in a series of management breakdowns at the Department of Children and Family Services, which oversees care of tens of thousands of abused or neglected minors. The agency has struggled in recent years to properly manage mistreatment investigations and children living under its oversight — and breakdowns have contributed to dozens of fatalities.

In an effort to revitalize the agency, Los Angeles County supervisors appointed Philip Browning in February to be the department's first permanent director in more than a year. Browning moved in recent weeks to fill vacancies in the department's executive team, which was decimated by resignations over the course of persistent scandals in recent years.

The auditor's report noted that Browning's team, which reviewed the mileage findings in draft form months ago, had already issued new guidelines and procedures to prevent future abuse of the reimbursement system, including a computer program that automatically calculates the distance between two points.

"The audit certainly highlights a lack of accountability," Browning said. "People just aren't using common sense. Frankly, we don't have any tolerance for people who falsify records."

Numerous employees were terminated or received suspensions as a result of the audit's findings, he said. Allegations against three staffers — including one woman who forged her boss' signature on a falsified mileage claim — were also referred to the Los Angeles County district attorney's office for possible criminal prosecution.

Decisions to remove children or reunite them with their families rely heavily on reports by the department's social workers, but the quality of the department's workforce has been repeatedly cited as a concern.

Criminal checks of employees have been lax, according to another recent audit, and no one in memory has flunked out of the department's training academy, according to recent statements by agency officials.